Lubricant



Patented Feb. 10, 1942 Carl F. Pru'tton, Cleveland Heights, Ohio,assignor, by mesne assignments, to The Lubri-Zol DevelopmentCorporation, Cleveland, Ohio, a

corporation otDelaware No Drawing.

Application December 12, 1938, Serial No. 245,225

4 Claims. (Cl. 252-39) As indicated, this invention relates to the fieldof lubrication and more particularly to the lubrl- ,1

cation of the working parts of certain types of internal combustionengines, especially Diesel engines. This application is a continuationin part of my co-pending application Serial No. 737,070,

filed July26,1934. I

Since Diesel engines generally operate under conditions of hightemperature and extreme pressure, considerable difficulty has beenencountered with the formation of gums and sludge in the crankcase andon theworking parts, neces-- culties of the type mentioned above may besubstantially reduced or overcome entirely.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends this invention,then, comprises the means hereinafter fully described and particularlypointed out in the claims. The following description sets forth indetail certain approved combinations of ingredients embodying theinvention, such disclosed means constituting, however, but certain ofthe various forms in which the principles of the invention may be used.

Broadly stated, this invention comprises the use as an addition agent inlubricating compositions and particularly in lubricating compositionsdesigned for use in Diesel engines of a material selected from the classconsisting of the products of the hydrolysis of a halogenated organicacid and the esters and salts derived from such hydrolyzed acids.

An example of one method of preparing a lubricant of the typecontemplated is as follows: Stearic acid is chlorinated until itcontains an amount of chlorine approximately equivalent to that ofdichlor-stearic acid (or preferably chlorinated. to a higher degree andthe lower chlorinated products removed), and the chlorinated stearicacid so formed is dissolved in an excess of an aqueous solution ofsodium hydroxide. The

solution then contains the sodium salt of the sulphuric acid, forexample, to, set free the hydrolyzed organic acid which, when hot,separates from the aqueous layer as a lighter, oilier layer.

About 1'/2% oi the hydrolyzed acid thus formed may'then be dissolved ina mineral lubricating oil of a type suitable for Diesel engine crankcaselubrication together with an amount of calcium hydroxide somewhat inexcess of that required to neutralize the acid. The mixture-is heatedslowly until it reaches a temperature of about 300 F. and held at thattemperature for about l2 hour. At this point a filter aid, such as clay,is preferably added in an amount of about .2% or less and the oilfiltered, for example, through a filter press while still hot to removethe excess lime and any other insoluble matter as well as to improve thecolor of the oil and thus produce the final product. This product maystill contain halogen if only part of the chlorine was removed byhydrolysis.

An alternative method of forming the calcium soap is to add a watersoluble inorganic calcium salt to the hydrolyzed sodium saltsolution anddissolve the water-insoluble calcium salt thus formed in oil.

Another example of a method of preparing a lubricant of the typecontemplated is-as follows: Stearic acid is chlorinated until itcontains an amount of chlorine equivalent to about 2 /2 atoms permolecule.

This chlorinated acid is then treated with steam until hydrogen chlorideis no longer evolved at an appreciable rate. The hydrolyzed acid thusobtained may be em; ployed in the same manner as that in the precedingexamples or any desired soap or ester may be prepared therefrom and usedas the lureagent, and the higher the temperature, the. greater is theprobability that substantially all 'of the halogen will have beenremoved by hydrolysis. Sodium hydroxide is a more efiective hydrolyzingagent than sodium carbonate, for example. Another factor aifecting thedegree of hydrolysis is the position of the halogen atoms on the acidmolecule, those in the a or 6 positions being relatively diflicult tohydrolyze. When the hydrolysis is carried on ata high temperature, acertain. amount of the halogen will be driven off in the form of ahydrogen halide such as 1101, for example, thus creating double bonds inthe molecules. The product of hydrolysis may, therefore, consist ofa-mlxture of' compounds containing halogen, double bonds, and hydroxylgroups, depending on the conditions under which the reaction wasconducted and the nature of the initial composition.

Acids other than stearic acid may be halogenated and treated asdescribed above to obtain products suitable for use in accordance withthis invention, for example:

Fatty acids, e. g.:

Caproic Oleic Lauric Linoleic Myristic Stearolic Palmitic LinolinicNaphthenic acids, 'e. g.:

Hexahydro benzoic acid Naphthenic acids derived from petroleum Aromaticfatty acids, e. g.:

Phenyl Stearic acid xenyl Palmitic acid Naphthyl Lauric acid AnthracylIt is to be understood, of course,'that the above examples are forillustration only and are not intended in any way to limit the scope ofthis invention.

These acids may contain various substituent groups such as:

Oxygen-bearing substituents:

The ether group The The carbonyl radicle,

For example as existing in Amides Aldehydes. Ketones Thio-acids andesters and salts of thio-acids Inorganic substituents in which theoxygen atom is directly attached to the carbon atom:

Oxime Oxygen-free substituents:

Amino, and substituted amino groups Imino Azo Hydrozo Hydrazine Nitrilelso nitrile Aryl, and substituted aryl, such as:

Phenyl Tolyl Naphthyl Xylyl Anthracyl Benzyl Alkyl, such as:

Methyl ropy Ethyl Isa-prow Of course, such substituent groups should notbe included as will render the particular final product oil-insoluble ordeleterious in its effect, i. e. unstable and corrosive.

Salts other than the calcium salts may be-employed when such salts aresufficiently oil-soluble and stable. Salts of magnesium, aluminum andzinc are generally suitable and also salts of organic bases where thesethemselves are not sludge-forming in character.

The following list illustrates a few of the types of alcohols suitablefor forming esters of the hydrolyzed halogenated acids in accordancewith my invention:

Methyl alcohol Ethyl alcohol Ethylene glycol (Monoand di-esters)Di-ethylene glycol (Monoand di-esters) Benzyl alcohol Chlor-benzylalcohol The final product has been found to possess many advantages overthe ordinary mineral oil lubricants. One of the most important is itsability to dissolve the gums and carbon binders which are usuallyresponsible for the formation of hard deposits, thus rendering suchdeposits soft and facilitating their removal. In a similar fashion, thegummy material in sludge is acted upon so that it can no longer carrysmall particles of grit and dirt which formerly have been re sponsiblefor much excessive wear. The addition agents of this invention areparticularly suited for their purpose since, in addition to theireffectiveness, they are quite stable to the high temperaturesencountered in use. Although strongly polar compounds and hence ofadvantage in enabling the lubricating composition to resist extremepressures of 10,000 lbs, per square inch and more, they are relativelynon-corrosive to the parts being lubricated.

Only small quantities of the addition agent need be employed inconjunction with the mineral oil base, concentrations of from about 0.1%to about 2% by weight of the salt or'ester, based on the amount ofmineral oil, and even smaller amounts of the hydrolyzed acid, oftenbeing quite sufficient to obtain the effect desired. For certain uses,however, it may be found desirable to employ up to about 10% or more.

Certain combinations of addition agents present various advantages, i.e.:

(1) Salt with acid (2) Salt with ester (3) Ester with acid (4) Salt,ester, and acid The solubility of the salt is improved by the presenceof a relatively small amount of an oil soluble acid. This acid may be:

(1) The hydrolyzed halogenated acid (2) The unhydrolyzed halogenatedacid (3) Any oil-soluble organic acid such as:

oleic, naphthenic Whenth'e hydrolyzed halogenated acid is employedalone, concentrations of about one-tenth of those given above for thesalts and esters are generally quite suficient. Stillsmaller percentagesof the acid maybe employed when the salt or ester is present. 'A typicalexample of such a composition isthe following:

' Per cent Oleic acid or'the acid formed by the hydrolysis ofchlorinated stearic acid 116 Salt 1.3 Mineral oil Remainder to indicateth'eability to form not only true solutions but also any form ofsubstantially permanently homogeneous composition when incorporated inmineral oil. With most of the compounds there is usuallylittle'dificulty, especially if the incorporation is efiected in themanner described in Cornell Patent No. 2,042,880, and since quite smallpercentages often give remarkably improved results it is seldom ofextreme importance that the addition agents be oil-soluble in allproportions. Also, for uses other than as crank-case lubricants, certaincompounds are of value as gelling or bodying agents when used in amountsgreater than are strictly soluble.

Since, in general, the loss of the addition agent by volatilization willbe less for compounds having a low volatility, the vapor pressure of thecompounds should, for most purposes, be 'less than atmospheric pressureat temperatures up to 140 C. It is usually desirable, especially for usein internal combustion engines, that; the vapor pressure be less thanatmospheric at temperatures up to 170 C. In th case of compounds whichare stable at temperatures up to their boiling points, this conditionmay be expressed by stating that the boiling point of the compoundshould, in general, be higher than 140 C., and for certain uses, such asin internal combustion enis the least expensive and one of the mosteffective ofthe halogens. Bromine and fluorine are more expensive andthe latter is relatively dithcult to --handle but they are each usablein accordance with this invention. Iodine is not so readily obtainableas the other halogens and is quite expensive but it also is satisfactoryin providing efiective addition agents. It should also be noted that twoor more difierent halogens may be'present in'the same molecule. Thebrom-chlor and .iiuorinated chlorine or bromine compounds giveespecially satisfactory results.

The fact that the addition agents of this invention'are more or lesscomplex mixtures, promotestheir oil-solubility and is probably partlyresponsive for their gum-solvent action. They are also highly polarcompounds and hence, strongly adsorbed.

While the lubricating compositions which have been described herein asillustrating one embodiment of the invention have been generallyreferred to as oils," i. e., liquids, this invention is, however, alsoapplicable to the solid and semisolid types of lubricants commonlyreferred to in the trade as greases, bodied oils, etc. In thisconnection is should be noted that certain of the addition agentscontemplated for use herein may be employed for tho additional purposeof bodying or thickening the lubricant to which they are added.

Other modes of applying the principle of the invention may be employed,chang being made as regards the details described, provided the featuresstated in any of the following claims, .or the equivalent of such, beemployed.

I therefore particularly point out and distinctly claim as my invention:

1. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition afiecting its use as an extreme pressurelubricant under conditions of temperagines, higher than 170 C. It shouldbe noted, in 7 this connection, that the addition agents of thisinvention are relatively non-volatile and, therefore, tend to remain inthe engine and perform their function. r

While mineral oil generally is the principal ingredient of thelubricant, it is not essential that it be the only ingredient other thanthe addition agent, provided that there be'no additional ingredientwhich is incompatible with such addition agent. It is within thecontemplation oi this invention to include, if necessary or desirable,such other addition agents as are commonly added to reduce the chemicalactivity or rate of oxidation, or to improve the viscosity index or coldtest of the lubricant, and a lubricating composition, according to thisinvention which also has a separate oiliness increasing agent has beenfound to be especially effective.

It is believed that under conditions of extreme pressure, th halogenatedaddition agents react chemically or physico-ch'emically with themetallic surfaces to form a nonefiuxing surface which will not seize orscore. This invention is not intended to be limited. however. by anyparticular theory or explanation of the action upon the metallicsurfaces.

All the various halogens are eifective when emlayed in accordance withthe present invention but chlorine is generally preferred inasmuch as itture and pressure such as normally exert a decomposing influence onorganic halogen compounds improved by the inclusion in the compositionof a minor amount, based on the amount of mineral lubricating oil, of ahalogen bearing hydroxy' organic composition selected from the classconsisting of: (a) the halogen bearing product produced by firsthalogenating an organic acid, then partially hydrolyzing the halogenatedorganic. acid to remove the relatively active halogen from the moleculeand substituting a hydroxyl group in place thereof; (b) the halogenbearing products produced by forming esters of the material identifiedunder (a) above; and (c) halogen bearing salts of the materialidentified under (a) above.

2. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricatin oil' with'theproperties of such composition afiecting'its use as an extreme pressurelubricant under conditions of temperature and pressure such as normallyexert a decomposing influence on organic halogen compounds improved bythe inclusion in the composition of a minor amount, based on the-amountof mineral lubricating oil, of a halogen bearing hydroxy organiccomposition selected from the class consisting of: (a) the halogenbearing product produced by first halogenating a fatty acid, thenpartially hydrolyzing the halogenated fatty acid to remove therelatively active halogen from the molecule and substituting a hydroxylgroup in place thereof; (b) the halogen bearing products produced byforming esters or the material a such composition aflecting its use asan extreme pressure lubricant under conditions of temperature andpressure such as normally exert a decomposing influence on organichalogen compound improved by the inclusion in the composition oi a minoramount, based on the amount or mineral lubricating oil, of a halogenbearing hydroxy organic composition selected from the the'molecule andsubstituting a hydroxyl group in place thereof; (b) the'halogen' bearingprod-. ucts produced by forming esters of the material identified under(a) above; (c) halogen bearing salts or the material identified under(a) above and (d) .any of (a) (b) an'df(c) together.

4. A lubricating composition containing as principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition afiecting its use as a lubricant underconditions of'pressure and temperature encountered in the lubricationoi.Diesel engines class consisting of (a) the halogen bearing prodnotproduced by first halogenating a fatty acid, then partially hydrolyzingthe halogenatedfatty acid to remove the. relatively active halogen fromimproved by the inclusion in the composition of from about 0.1% to about2% by weight, based on the amount of 011,, of a halogen bearing calciumsalt or a partially hydrolyzed halogenated fatty acid. j

1 CARL F. PRUTTON.

